Nuclear Physics A 836 (2010) 1–10 www.elsevier.com/locate/nuclphysa Probing the 6,7 Li nucleon densities through a new break-up process approach D.P. Sousa a , D. Pereira a,∗ , J. Lubian b , L.C. Chamon a , J.R.B. Oliveira a , E.S. Rossi Jr. a , C.P. Silva a , P.N. de Faria a , V. Guimarães a , R. Lichtenthaler a , M.A.G. Alvarez c a Instituto de Física da Universidade de São Paulo, DFN, C.P. 66318, 05315-970, São Paulo, SP, Brazil b Instituto de Física, Universidade Federal Fluminense, 24210-340, Niterói, RJ, Brazil c Departamento de Fisica Atomica Molecular y Nuclear da Universidade de Sevilla, Apdo. 1065, E-41080, Sevilla, Spain Received 7 October 2009; received in revised form 13 January 2010; accepted 14 January 2010 Available online 6 February 2010 Abstract In this work we present a double folding optical model analysis of new near-barrier quasi-elastic exper- imental data for the 6,7 Li + 120 Sn systems. From the analysis, it was possible to confirm the ground-state nucleon densities assumed for the weakly bound 6,7 Li isotopes. The apparent discrepancies between the experimental densities and those based on Dirac–Hartree–Fock–Bogoliubov (DHB) calculations were re- moved. A new approach that simulates the projectile break-up and a positive polarization from couplings of 6,7 Li bound states with the continuum was considered in the reaction mechanism.  2010 Elsevier B.V. All rights reserved. Keywords: NUCLEAR REACTIONS 120 Sn( 6 Li, X), E lab = 19.5 MeV; 120 Sn( 7 Li, X), E lab = 19.5, 20.5, 5.25 MeV; measured elastic and quasi-elastic σ(θ) using silicon barrier detectors; deduced optical model parameters, sensitivity radius, nuclear densities and introduced new imaginary potential component * Corresponding author. Fax: +55 11 3031.2742. E-mail address: dpereira@dfn.if.usp.br (D. Pereira). 0375-9474/$ – see front matter  2010 Elsevier B.V. All rights reserved. doi:10.1016/j.nuclphysa.2010.01.245